Need rat help NOW

[Sorraia]

There's no need to kill them, it is treatable. The vet can do one of several things, but basically boils down to a topical or oral medication. I personally prefer oral ivermectin, but that can be tricky getting the right dosage. Many people use a topical product (which still needs the right dosage, but isn't quite as easy to overdose at the oral). If you are taking them to the vet, he/she will be able to prescribe the appropriate medication for them.

In the mean time...
You can bathe them with a kitten shampoo that contains pyrethrin. The pyrethrin is toxic to the lice or mites (depending on which your rats have) and will help kill some of them. An oatmeal shampoo can also offer your rats temporary relief from the itching. You can also put olive oil on them, which is completely non-toxic to the rats, will offer them some relief from the itching, and is said to suffocate the mites/lice. It will make a greasy mess too.

Make sure you clean their cages well. Any clean substrate needs to be microwaved or put in the freezer to kill and mites/lice living in it. That's the mostly likely way they got into your home in the first place.